Pastel Seafoam vs Phoenix Egg

How close are they?

ΔE 29.6, loose: different enough that you should pick on purpose. Phoenix Egg is more saturated, warmer than Pastel Seafoam.

Can I use Phoenix Egg instead of Pastel Seafoam?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 30). Phoenix Egg is more saturated, warmer than Pastel Seafoam.

Can I use Pastel Seafoam instead of Phoenix Egg?

The same difference applies the other way round: Pastel Seafoam is more muted, cooler.

ΔE is the colour difference between our two swatch estimates: under about 6 is close, over about 15 is loose. Real paints also differ in finish, coverage and how they thin, so test before you commit.